LAGOS Spatial Analysis

LAGOS Analysis

Loading in data

First download and then specifically grab the locus (or site lat longs)

#Lagos download script
# LAGOSNE::lagosne_get(dest_folder = LAGOSNE:::lagos_path())


#Load in lagos
lagos <- lagosne_load()

## Warning in (function (version = NULL, fpath = NA) : LAGOSNE version unspecified,
## loading version: 1.087.3

#Grab the lake centroid info
lake_centers <- lagos$locus


# load('lake_centers.Rdata')

Convert to spatial data

#Look at the column names
#names(lake_centers)

#Look at the structure
#str(lake_centers)

#View the full dataset
#View(lake_centers %>% slice(1:100))

spatial_lakes <- st_as_sf(lake_centers,coords=c('nhd_long','nhd_lat'),
                          crs=4326) %>%
  st_transform(2163)

#Subset for plotting
subset_spatial <- spatial_lakes %>%
  slice(1:100) 

subset_baser <- spatial_lakes[1:100,]

#Dynamic mapviewer
mapview(subset_spatial)

Subset to only Minnesota

states <- us_states()

#Plot all the states to check if they loaded
#mapview(states)
minnesota <- states %>%
  filter(name == 'Minnesota') %>%
  st_transform(2163)

#Subset lakes based on spatial position
minnesota_lakes <- spatial_lakes[minnesota,]

#Plotting the first 1000 lakes
minnesota_lakes %>%
  arrange(-lake_area_ha) %>%
    slice(1:1000) %>%
  mapview(.,zcol = 'lake_area_ha')

In-Class work

1) Show a map outline of Iowa and Illinois (similar to Minnesota map upstream)

#Show a map outline of Iowa and Illinois 

i_states <- states %>% 
  filter(name %in% c('Iowa','Illinois')) %>% 
  st_transform(2163)

mapview(i_states)

2) Subset LAGOS data to these sites, how many sites are in Illinois and Iowa combined? How does this compare to Minnesota?

#Subset LAGOS data

istate_lakes <- spatial_lakes[i_states,]

nrow(minnesota_lakes)-nrow(istate_lakes)

## [1] 12572

There are 16446 sites in Illinois and Iowa combined. Meanwhile, there are 29038 Minnesota sites, exceeding the number of sites in Illinois/Iowa by 12572 sites.

3) What is the distribution of lake size in Iowa vs. Minnesota?

• Here I want to see a histogram plot with lake size on x-axis and frequency on y axis (check out geom_histogram)

states_lagos <- lagos$state %>% 
  select()

iowa <- states %>%
  filter(name == 'Iowa') %>%
  st_transform(2163)

iowa_lakes <- spatial_lakes[iowa,]
  

ggplot(iowa_lakes, aes(x=lake_area_ha))+ 
  geom_histogram(bins=40)+ 
  scale_x_log10(labels= scales::comma)+
  labs(x= "Lake size (hectares)", y= "Frequency", title='Iowa Lakes')

ggplot(minnesota_lakes, aes(x=lake_area_ha))+ 
  geom_histogram(bins=40)+ 
  scale_x_log10(labels=scales::comma)+
  labs(x= "Lake size (hectares)", y= "Frequency", title='Minnesota Lakes')

The distributions of lake size for both Iowa and Minnesota are positively skewed. Generally, Iowa lake size is smaller than Minnesota.

#figuring out facet wrap
# all_spatial_lakes <- bind_rows(iowa_lakes,minnesota_lakes)
# 
# ggplot(all_spatial_lakes, aes(x=lake_area_ha))+ 
#   geom_histogram(bins=40)+ 
#   scale_x_log10()+
#   labs(x= "Lake size (hectares)", y= "Frequency")+ 
#   facet_wrap()

4) Make an interactive plot of lakes in Iowa and Illinois and color them by lake area in hectares.

istate_lakes %>%
  arrange(-lake_area_ha) %>%
  slice(1:1000) %>%
  mapview(., zcol = 'lake_area_ha', at=c(0,100,250,500,1000,2500,5000,10000), layer.name='Lake area (ha)', canvas=TRUE)

5) What other data sources might we use to understand how reservoirs and natural lakes vary in size in these three states?